Such a One vibration damper is known from DE 44 41 047 C1. A piston which is guided axially within a cylinder barrel has provided on it pressure-dependent damping valves for exchange of fluid, during the rebound and compression stages, between two working chambers. Pilot control causes a controllable pressure to be built up in pilot-control chambers. The pilot pressure forces the disks of the damping valves into their closed position. Through a duct system, fluid is directed from the working chambers into the pilot-control chambers and therefore the pressure there is increased. The pilot pressure is regulated with the aid of an externally adjustable pilot valve, which is arranged in the duct system. An element separates off the pilot-control chamber and the working chamber. Fluid can flow out from the pilot valve, via outflow passages, into the respectively pressure-free working chamber.
Such a vibration damper is also described in German patent application 10 2014 115 577.7, which has not yet been published.
The valve disks give the vibration damper usually a degressive damping behavior at high piston speeds, at which the valve disks end up being raised off from the valve seat. The opening cross section here increases as speed increases, which triggers the degressive behavior.
Patent application 10 2014 116 264.1, which has not yet been published, describes a development of the aforementioned vibration dampers. Alongside the damping via the valve disks, one or more bypass ducts form, within the piston, a throttle between the working chambers, and said throttle gives a progressive component to the damping behavior of the vibration damper. The influence of this progressive component is important in particular at low piston speeds, at which the valve disks still lie fully against the valve seat. The bypass duct is formed in the piston. The bypass duct here is covered by different sizes of check-valve disks on either side of the piston, and this gives rise to different bypass throughflow cross sections for the two throughflow directions.
It is the object of the present invention to develop Thus a need exists for a cost-effective configuration which that provides an alternative to German patent application 10 2014 116 264.1 and in which use can be made of a standard piston, although it is nevertheless possible to realize different bypass throughflow cross sections for the two throughflow directions. The solution should be capable of being implemented in a cost effective manner.